Research will include investigation of several different aspects of the vasomotor control of liver blood flow. Work will be done on in situ, surgically isolated, autoperfused canine livers. Hepatic arterial and portal venous flows will be measured by an electromagnetic blood flowmeter. Hepatic arterial and intrahepatic portal venous vascular resistances will be calculated. The phenomenon of autoregulatory escape and the function of alpha and beta adrenergic receptor sites in the liver vasculature will be studied in detail. Also the hemodynamic response of the liver and mesenteric vessels to the infusion and amino acids will be investigated. Response of the liver vasculature to acute elevations of biliary pressure will be explored. The function of hepatic arterial-portal venous shunts will also be investigated.